At the time of carrying out an infusion on a patient, or in other similar situations, an indwelling needle connected to an infusion line is made to puncture a blood vessel and indwell there, thereby performing the infusion operation.
Such an indwelling needle is composed of a hollow outer needle, an outer-needle hub firmly attached to a proximal end (base end) of the outer needle, an inner needle inserted into the outer needle and having a sharp point at a distal end (tip) thereof, and an inner-needle hub firmly attached to a proximal end (base end) of the inner needle (see, for example, Patent Document 1).
When the indwelling needle is made to puncture a patient's blood vessel, a puncturing operation is performed in an assembled condition, where the inner needle is inserted into the outer needle and the point of the inner needle protrudes from the distal end of the outer needle. In such an assembled condition, generally, a connector of an infusion line is connected with the outer-needle hub.
Then, when the point of the inner needle has reached the inside of the blood vessel, blood having flowed in through the opening at the point passes through the inner cavity (lumen) of the inner needle, and flows into the inside of the transparent inner-needle hub (flashback). This makes it possible to confirm (visually recognize) that the inner needle has securely punctured the blood vessel.
Upon confirmation of flashback, the outer needle is advanced, with the inner needle as a guide, so as to become inserted into (puncture) the blood vessel.
Next, while gripping the outer needle by hand, the inner needle is pulled out of the outer needle. Then, an infusion agent is administered through the connected infusion line and the outer needle.
Meanwhile, the outer-needle hub is formed with a finger hold (tab), which is pressed by a finger (index finger) in order to move the outer needle in the distal direction. The finger hold is formed perpendicular to the axis of the outer needle, and a surface thereof on the proximal side is pressed by the finger.
In the aforementioned existing indwelling needle assembly, however, the finger hold is oriented vertically to the axis of the outer needle, and hence, the following problem has occurred. When the outer needle is moved in the distal direction, an attempt to press the finger hold straight along the axis of the outer needle, namely, in a direction parallel to the axis may result in a force, which acts in a downward direction relative to the axis (in a direction opposite to the direction of projection of the finger hold), thus causing an inconvenience such as bending of the outer needle, and making it difficult to move (advance) the outer needle smoothly. In short, the indwelling needle assembly has been poor in operability at the time of performing a puncturing operation.
Further, in the existing indwelling needle assembly, an attempt to move the outer needle in parallel with the axis thereof when the outer needle is moved in the distal direction may result in a force being exerted in a downward direction relative to the axis, thus causing an inconvenience in that a distal-side portion of the axis of the outer needle becomes inclined downwardly (downward deviation), or the outer needle becomes bent. Thus, it has sometimes been difficult to move (advance) the outer needle smoothly. In short, in this case as well, the indwelling needle assembly has been poor in operability at the time of performing a puncturing operation.
Patent Document 1: Japanese Laid-Open Patent Publication No. 10-179734